feat(message): add conversation notification mute feature

Add notification mute functionality for conversations with the following changes:

- Add notification_muted field to ConversationResponse and related DTOs
- Add notificationMutedMap to message store for tracking mute state
- Add setConversationNotificationMuted API method
- Integrate mute toggle in GroupInfoScreen and PrivateChatInfoScreen
- Skip system notifications for muted conversations
- Suppress vibration for muted conversations in WS handler
- Clean up selected mentions when @mentions are removed from text

Chore changes:
- Update PostCard bookmark icon from 'bookmark' to 'star'
- Refine card styles across AppsScreen, MaterialsScreen, and SubjectMaterialsScreen
- Improve week selector scrolling to center selected week in ScheduleScreen

src/services/message/messageService.ts

@@ -274,6 +274,12 @@ class MessageService {
     });
   }
 
+  async setConversationNotificationMuted(conversationId: string, notificationMuted: boolean): Promise<void> {
+    await api.put(`/conversations/${encodeURIComponent(conversationId)}/notification_muted`, {
+      notification_muted: notificationMuted,
+    });
+  }
+
   // ==================== 消息相关 ====================
 
   /**